Glucose is a simple sugar that is 40% carbon, 6.7% hydrogen, and 53.3% oxygen. What is its empirical formula?

Answer 1

Assume you have 100 g of material. Then you can equate % to grams and then to moles.

40 g C x 1 mol C / 12 g = 3.33 moles C

6.7 g H x 1 mol H / 1 g = 6.7 moles H

53.5 g O x 1 mol O / 16 g = 3.34 moles O

Now divide all by 3.33 to try to get them all to be whole numbers...

3.33 moles C / 3.33 = 1.00 moles C

6.7 moles H / 3.33 = 2.0 moles H

3.34 moles O / 3.33 = 1.0 moles O

Empirical formula = CH₂O